﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace HJ212_Common
{
    /*
    /// <summary>
    /// CRC16算法
    /// 调用
    ///      byte[] by = new byte[2];  
            by[0] = Convert.ToByte("79", 16);  
            by[1] = Convert.ToByte("83", 16);  
            ClassInfo.CRC16 CRC = new CRC16();
            MessageBox.Show(CRC.CalculateCrc16(by).ToString("X")); 
    /// </summary>
     * */
    public class CRC16
    {

        public CRC16()
        {
        }


        private readonly byte[] _auchCRCHi = new byte[]//crc高位表  
        {  
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,   
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,   
            0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,   
            0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,   
            0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,   
            0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,   
            0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,   
            0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,   
            0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,   
            0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,   
            0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,   
            0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,   
            0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,   
            0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,   
            0x80, 0x41, 0x00, 0xC1, 0x81, 0x40  
        };

        private readonly byte[] _auchCRCLo = new byte[]//crc低位表  
        {  
            0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,   
            0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,   
            0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,   
            0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,   
            0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,   
            0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,   
            0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,   
            0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,   
            0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,   
            0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,   
            0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,   
            0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,   
            0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,   
            0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,   
            0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,   
            0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,   
            0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,   
            0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,   
            0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,   
            0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,   
            0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,   
            0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,   
            0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,   
            0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,   
            0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,   
            0x43, 0x83, 0x41, 0x81, 0x80, 0x40  
        };


        public ushort CalculateCrc16(byte[] buffer)
        {
            byte crcHi = 0xff;  // 高位初始化  

            byte crcLo = 0xff;  // 低位初始化  

            for (int i = 0; i < buffer.Length; i++)
            {
                int crcIndex = crcHi ^ buffer[i]; //查找crc表值  

                crcHi = (byte)(crcLo ^ _auchCRCHi[crcIndex]);
                crcLo = _auchCRCLo[crcIndex];
            }

            return (ushort)(crcHi << 8 | crcLo);
        }



        //CalculateCrc16返回的是一个ushort类型的值，如果要返回Crc高字节和低字节，可重写CalculateCrc16函数为：  
        public ushort CalculateCrc16(byte[] buffer, out byte crcHi, out byte crcLo, int CRC_LEN)
        {
            crcHi = 0xff;  // high crc byte initialized  
            crcLo = 0xff;  // low crc byte initialized  

            for (int i = 0; i < buffer.Length - CRC_LEN; i++)
            {
                int crcIndex = crcHi ^ buffer[i]; // calculate the crc lookup index  

                crcHi = (byte)(crcLo ^ _auchCRCHi[crcIndex]);
                crcLo = _auchCRCLo[crcIndex];
            }

            return (ushort)(crcHi << 8 | crcLo);
        }





        public string CRC16_T212_old(string strSource)//CRC校验
        {
            //int i = 0;
            int j = 0;
            int len = 0;
            int crc = 0;
            int tc = 0;
            int sc = 0;
            crc = 0xffff;
            len = strSource.Length;

            foreach (char chr in strSource)
            {
                tc = ((int)chr) * (int)(Math.Pow(2, 8));
                //左移8位 
                crc = (tc ^ crc);
                for (j = 1; j <= 8; j++)
                {
                    sc = crc & 0x1;
                    crc = crc / 2;
                    if ((sc != 0)) crc = (crc ^ 0xa001);
                }
            }

            return crc.ToString("X");

        }


        public string CRC16_T212(string strSource)//CRC校验 据赵新杰说是万维的算法
        {
            int hi;
            int i = 0;
            int j = 0;
            int len = 0;
            int crc = 0;
            int tc = 0;
            int sc = 0;
            crc = 0xffff;
            len = strSource.Length;
            string rslt = "";
            foreach (char chr in strSource)
            {
                hi = crc >> 8;
                hi ^= chr;
                crc = hi;
                //tc = crc * (int)(Math.Pow(2, 8));
                ////左移8位
                //crc = (tc ^ crc);
                for (j = 1; j <= 8; j++)
                {
                    sc = crc & 0x1;
                    crc = crc >> 1;
                    if ((sc != 0)) crc = (crc ^ 0xa001);
                }
            }
            rslt = "0000" + crc.ToString("X");
            return rslt.Substring(rslt.Length - 4);
        }

        public string CRC16HJ212(string strSource)   //根据 HJ/T212-2005环境仪器传输标准编写
        {
            int tmpReg;
            int i, j;

            int CrcReg = 0xffff;
            string rslt = "";
            foreach (char chr in strSource)
            {
                tmpReg = chr;
                tmpReg <<= 8;       //HJ/T212-2005协议标准规定使用高字节进行运算

                CrcReg ^= tmpReg;    //按HJ/T212协议规定是【高字节】参与异或  

                for (i = 0; i < 8; i++)
                {
                    if ((CrcReg & 0x0001) == 1)
                    { //如果即将移出位是1
                        CrcReg >>= 1;        //右移1位 
                        CrcReg ^= 0xa001;    //异或生成多项式 POLY = X^16+X^15+X^2+X+1 
                    }
                    else
                    {         //如果即将移出位是0
                        CrcReg >>= 1;        //只右移,而不异或
                    }
                }
            }
            rslt = "0000" + CrcReg.ToString("X");
            return rslt.Substring(rslt.Length - 4);        //HJ/T212-2005标准要求高位先发送
        }


    }
}
